hw.usb.ehci.no_hs This tunable disables USB devices to attach like HIGH-speed ones and will force all attached devices to attach to the FULL- or LOW-speed companion controller. The default value is 0 (off).

Steve

Steve I had a similar problem to the OP on my X9SCV build. {irq16: ehci0} was using ~50% of one cpu. I did as you suggested and added hw.usb.ehci.no_hs="1" to loader.conf and it seems to have fixed it. I'll keep an eye on it. Thanks

Dear All, I've read this topic carefully and tried many ways to solve this problem. But there is no result till now.

I use pfsense 2.0.1 release (amd64) with ZOTAC®LGA 1155 Z68-ITX, Intel Celeron G530, Box, 2x2.4 GHz, 2 GB DDR3, HDD WD2500AAKX, 2 x onboard Realtek RTL8111E and AzureWave AR5B95. My ISP gives me 1 Gbps full duplex uplink and static IP. So everything good and I have realy 800-900 Mbps throughput, but only one bad. Last time I noticed interrupts on CPU 30-40%, and I saw this on irq16: ath0 ehci0. I disabled USB3, disabled Audio-controller and other unused things in BIOS. No result. Then I removed the WiFi card AR5B95 and CPU load slow down to 20-30%. I tried to change loader.conf with hw.usb.ehci.no_hs="1" and rebooted the system. But no result again. This is a link to RRD graphs.

Here is the output from $ vmstat -i and $ devinfo -v, to illustrate the problem:

Update. Problem solved!Point is that motherboard Z68-ITX has video only with HDMI 1.4a or with DisplayPort (mini-DP). So I connected LCD TV in to HDMI, installed pfsense, assigned interfaces, entered commands for loader.conf, etc. But I did not disconnected the HDMI after it.

Then on the russian pfSense forum guys asked me about HDMI/mini-DP and suggested to disconnect LCD. I did it without shutting down the router and looked into vmstat -i. The interrupts appeared on irq16: ehci0 immediately after I disconnected the cable.

After I disconnected the display then I rebooted the router. After it I haven't seen the problem again.

If you don't have a high packet rate on em1 and are bothered by the high interrupt rates I would be inclined to see if I could stop use of of irq16 and see how things change. For example, move USB devices to different USB sockets in an attempt to move them to ehci1, the other USB controller. The BIOS might allow disabling of USB. Does that change the interrupt rate on irq16? Disable em1. Does that change interrupt rate on irq16?

You could also try installing a snapshot build of pfSense 2.1. It is based on a much more recent release of FreeBSD which might work better with your hardware.